Misc bug fixes for new normalization

refs #5955

Fixed files being identified more than once - FilesIdentifiedIDs is updated
on the second identification, not another row created.  Fixed manual
normalization and default rule bugs.  Added skipping based on file group
use.
More misc bug fixes for normalization changes

refs #5955

Remove transcoderNormalizer dependency and fprule registering from
archivematicaClient.  Enable thumbnail processing in normalize.py.  Add
thumbnail normalizing to the preservation & access chain.  Remove now
unneeded reminder to restart MCPClient.